Quaternary landscape dynamics boosted species dispersal across Southeast Asia

Sundaland, the inundated shelf separating Java, Sumatra and Borneo from the Malay Peninsula, is of exceptional interest to biogeographers for its species richness and its position at the junction between the Australasian and Indomalay biogeographic provinces. Owing to its low elevation and relief, its physiography is contingent on relative sea-level change, which drove Quaternary species burst in response to flooding episodes. New findings show that the region was predominantly terrestrial during the Late Pleistocene requiring a reassessment of the drivers of its recent biodiversity history. Here we show that physiographic changes have modified the regional connectivity network and remodelled the pathways of species dispersal. From combined landscape evolution and connectivity models, we found four phases of drainage reorganisation and river captures. These changes have fragmented the environment into multiple habitats connected by migratory corridors that cover 8% of the exposed shelf and stretch across the biogeographic provinces. Our results support the theory that rapidly evolving physiography could foster Quaternary biodiversification across Southeast Asia.

Distribution of the Mexican saucer bug Ambrysus signoreti Stål, 1862 (Heteroptera, Nepomorpha, Naucoridae, Ambrysinae)

The geographic range of the saucer bug Ambrysus signoreti Stål, 1862 is reported and mapped for the first time. Results are based on records from approximately 1,700 specimens examined from seven collections. New distribution records are presented from the Mexican states of Coahuila, Hidalgo, Nuevo León, Querétaro, San Luis Potosí, and Tamaulipas. This species is exclusively distributed in the eastern part of Mexico, in the Sierra Madre Oriental, Tamaulipas, and Veracruzan biogeographic provinces.

Mammals of the Natural National Park Selva de Florencia, Caldas, Colombia

The Department of Caldas, Central Andes of Colombia, has two National Natural Parks protecting strategic Andean ecosystems. However, the available information on mammals in these protected areas has not been compiled or updated recently. Here, we present an updated inventory of the mammals present in the Selva de Florencia National Natural Park. To construct the inventory, we used historical (museum vouchers) and recent records obtained during field activities over the last 20 years. We used several trapping methods including Sherman and Tomahawk traps, mist nets, and camera traps. We documented 81 mammal species belonging to nine orders, 25 families and 59 genera. Bats (Chiroptera: 30 spp.), rodents (Rodentia: 17 spp.), and carnivores (Carnivora: 13 spp.) were the most diverse groups, representing 73.2 % of recorded species. We also recorded orders such as Didelphimorphia (8 species), Primates (5), Pilosa (3), Artiodactyla (2), Cingulata (2), and Eulipotyphla (1). Also, we recorded two endemic species (Marmosops chucha and Cryptotis colombianus) and two new species for the Department of Caldas (Bassaricyon neblina and Heteromys aff. anomalus). These species constitute elements of the Andean region and the Nor-Andean and Chocó-Magdalena biogeographic provinces. We highlight the presence of four endangered primates (Aotus lemurinus, Ateles hybridus, Cebus versicolor, and Saguinus leucopus), two of which are endemic to Colombia: S. leucopus and C. versicolor. This work is the baseline to update the management plan of the protected area, from the review of its conservation targets, the definition of the specific management goals, to its effective monitoring.

Threat patterns and conservation status of endemic vascular flora in Argentina: a quantitative perspective

Global warming, coupled with habitat destruction and human activity, are accelerating the rates of species extinction worldwide. Species-extinction risk assessment, using the IUCN Red List categories, together with the study of the spatial patterns of biodiversity, are fundamental approaches to identify conservation priorities and targeting government decisions to mitigate impacts on biodiversity. Here, we analyzed threat levels of endemic species for the entire Argentinean vascular flora. Accordingly, we classified species following the IUCN threat categories and analyze threat levels on the different families, plant life-forms, and biogeographic regions of the country. We also analyzed spatial patterns of threat by means of macroecological modeling techniques, and explored the effectiveness of current protected areas in relation to the threatened endemics they actually included. The results showed that of the 1683 Argentinean endemic taxa, 800 species were here categorized under threat (VU, EN, or CR) (~47%). Families with the highest number of threatened species were also those with the highest number of endemics; herbs and climbing plants presented significantly higher threat levels, and among biogeographic provinces, the most affected in terms of threat proportion were the Altoandina, Yungas, and Paranaense. In addition, different hotspots of threatened endemism were detected, mainly associated with mountainous areas with high altitudinal heterogeneity; of these, only nearly half are included, at least partially, within a protected area. An up-to-date species list of Argentinean endemics, including their proposed conservation status, is also provided. This work seeks to contribute to the knowledge on geographical patterns of the Argentinean flora and its conservation, complementing the information published in the Flora of Argentina.

Ecology of Plant Communities in Central Mexico

In Central Mexico converge three biogeographic provinces: Altiplano sur, Sierra Madre Occidental and Costa del Pacífico. Each one of them is composed by different plant communities: Thorn Forest, Temperate Mountain Forest and Dry Tropical Forest respectively. Our objective is to show, through phytoecological analysis, the species richness, diversity and the structure of the plant communities from the Temperate Mountain Forest and from the Tropical Dry Forest. In the Temperate Mountain Forest, 50 forest species were recorded, with a Shannon Wiener diversity index H´ = 1.63 on altitudes from 2400 to 2600 m. The Whittaker β index is Bw = 7.22. In the tropical dry forest, we identified 79 plants species with a mean diversity index H´ = 3.49 on altitudes from 1951 to 2100 m. In this ecosystem the Bw index is 8.12. This study offers important information for the establishment of management practices, considering the protection status from the areas in which this vegetation type is distributed.

Increase in marine provinciality over the last 250 million years governed more by climate change than plate tectonics

Amidst long-term fluctuations of the abiotic environment, the degree to which life organizes into distinct biogeographic provinces (provinciality) can reveal the fundamental drivers of global biodiversity. Our understanding of present-day biogeography implies that changes in the distribution of continents across climatic zones have predictable effects on habitat distribution, dispersal barriers and the evolution of provinciality. To assess marine provinciality through the Phanerozoic, here we (a) simulate provinces based on palaeogeographic reconstructions and global climate models and (b) contrast them with empirically derived provinces that we define using network analysis of fossil occurrences. Simulated and empirical patterns match reasonably well and consistently suggest a greater than 15% increase in provinciality since the Mesozoic era. Although both factors played a role, the simulations imply that the effect of the latitudinal temperature gradient has been twice as important in determining marine provinciality as continental configuration.

Diversity, species richness distribution and centers of endemism of Lycianthes (Capsiceae, Solanaceae) in Mexico

Spatial patterns of plant diversity matter. Identifying areas of high species richness and endemism are crucial for understanding the evolution of plant diversity and community assemblages as well establishing sustainablility and conservation priorities. Lycianthes is the third most species-rich genus in the Solanaceae with 187 taxa (152 species, 10 subspecies and 25 varieties) native to the Americas and Asia-Pacific region. However, the distributions of the taxa are uneven and usually concentrated along mountain ranges in the Neotropic. In Mexico, the main mountain chains are known as the Mexican Transition Zone (MTZ), so we expected the highest species richness and endemism to be found there. Our aims were twofold; first, to determine the Lycianthes species richness in Mexico; and second, to analyze the spatial patterns. We used 2305 georeferenced records obtained from specimens examined in herbaria, electronic specimen databases and specimens cited in the literature. Then, we analyzed species richness and endemism using a grid-cell of 50 × 50 km, political divisions, biogeographic provinces, vegetation types, and elevation. In addition, endemism was quantified using weighted endemism (WE) and corrected weighted endemism (CWE). In Mexico, there were 48 taxa of Lycianthes, which included 44 species and four varieties. Of these, 20 species and two varieties were endemic. We found 14 cells of high species richness and eight centers of endemism, all located across the MTZ. The pine-oak forest resulted in the richest plant community followed by the cloud forest along an elevational gradient of 1000–2000 m. Likewise, endemism was found within the pine-oak forest of the MTZ, between 1000–2000 m of elevation. The geological history and climatic conditions of the MTZ could explain the diversity of Lycianthes there.

Selva Zoque, Mexico: an important Mesoamerican tropical region for reptile species diversity and conservation

The Selva Zoque region is characterized by a great variety of ecosystems for which there is little information about reptile species diversity and their conservation status. This study is the first assessment of the species richness, composition, and conservation status of reptiles of this region. Additionally, this information is compared with that of seven other tropical regions in northern Mesoamerica. In total, 141 native reptile species belonging to 81 genera and 29 families are recorded for the Selva Zoque region. Sixty species (42% of the total) recorded in Selva Zoque are in high-risk categories according to the Mexican Ministry of the Environment, the highest number for the Mexican regions of Mesoamerica. According to the IUCN, six species are in high-risk categories, seven species are in Data Deficient, and 23 (16%) have not been evaluated yet. According to the Environmental Vulnerability Scores approach, 28 species (20%) are in the high vulnerability category. The Selva Zoque species composition is most similar to Los Tuxtlas and Lacandona regions, and most dissimilar to Sian Ka´an Biosphere Reserve. The reptilian fauna of Selva Zoque has a distinctive composition, with the highest number (11 species) of endemic reptiles in the northern Mesoamerican, and species from two biogeographic provinces: the Gulf of Mexico and the Mexican Pacific Coast. These results indicate that the Selva Zoque is the most diverse region in native reptile species in northern Mesoamerica, highlighting it as extremely important for the conservation of the reptile fauna at local (southern Mexico) and regional levels (northern Mesoamerica).

Transition zones and biogeographic characterization of endemism in three biogeographic provinces of central Mexico

Background: Sites of overlap in the species distribution among regions are known as transition zones. Their floristic and biogeographic complexity is rarely discussed. Questions: Is it possible to identify transition zones amid the biogeographic provinces of Mexico? Can transition zones also be considered areas of endemism? Study species: 315 Asteraceae taxa endemic to Mexico.Study site: Volcanic Belt, Balsas Depression and Sierra Madre del Sur biogeographic provinces. Methods: For species of Asteraceae endemic to three biogeographic provinces of central Mexico, we characterized the province to which each species belonged and estimated the distance it could penetrate the neighboring province. We defined transition zones between biogeographic provinces as the average penetration distances of the species. We also evaluated the presence of species with restricted distribution to transition zones. Results: Two transition zones were identified in the Balsas Depression, first, at the junction with the Volcanic Belt with a width of 13 km, and second, with the Sierra Madre del Sur, with a width of 12.3 km. There were 45 species whose distribution was restricted to those transition zones.Conclusions: Understanding how richness and endemism are exchanged from one region to another is essential to explain how their floras have been assembling and evolving. This analysis has allowed us to better understand the relationships among regions as complex as those studied here.

Exploring the Microdiversity Within Marine Bacterial Taxa: Toward an Integrated Biogeography in the Southern Ocean

Most of the microbial biogeographic patterns in the oceans have been depicted at the whole community level, leaving out finer taxonomic resolution (i.e., microdiversity) that is crucial to conduct intra-population phylogeographic study, as commonly done for macroorganisms. Here, we present a new approach to unravel the bacterial phylogeographic patterns combining community-wide survey by 16S rRNA gene metabarcoding and intra-species resolution through the oligotyping method, allowing robust estimations of genetic and phylogeographic indices, and migration parameters. As a proof-of-concept, we focused on the bacterial genus Spirochaeta across three distant biogeographic provinces of the Southern Ocean; maritime Antarctica, sub-Antarctic Islands, and Patagonia. Each targeted Spirochaeta operational taxonomic units were characterized by a substantial intrapopulation microdiversity, and significant genetic differentiation and phylogeographic structure among the three provinces. Gene flow estimations among Spirochaeta populations support the role of the Antarctic Polar Front as a biogeographic barrier to bacterial dispersal between Antarctic and sub-Antarctic provinces. Conversely, the Antarctic Circumpolar Current appears as the main driver of gene flow, connecting sub-Antarctic Islands with Patagonia and maritime Antarctica. Additionally, historical processes (drift and dispersal limitation) govern up to 86% of the spatial turnover among Spirochaeta populations. Overall, our approach bridges the gap between microbial and macrobial ecology by revealing strong congruency with macroorganisms distribution patterns at the populational level, shaped by the same oceanographic structures and ecological processes.